fix(typings): allow CorsOptionsDelegate as cors options (#641)
fix(typings): allow CorsOptionsDelegate as cors options (#641)

Reference: https://www.npmjs.com/package/cors#configuring-cors-asynchronously

Related: https://github.com/DefinitelyTyped/DefinitelyTyped/commit/54a59cd8f0bdbee257ada2716fdc1b7c94909c40
socketio/engine.io,socketio/engine.io